Ferrule for optical wave guide

ABSTRACT

An apparatus includes an optical wave guide and a ferrule. The optical wave guide has a prespecified horizontal-positioning surface and a prespecified vertical-positioning surface. The ferrule is to precisely couple with the optical wave guide. The ferrule defines a first datum plane mating with the prespecified vertical-positioning surface of the optical wave guide to precisely mechanically vertically position the optical wave guide within the ferrule. The ferrule defines a second datum plane mating with the prespecified horizontal-positioning surface of the optical wave guide to precisely mechanically horizontally position the optical wave guide within the ferrule.

RELATED APPLICATIONS

The present patent application is a continuation of the previously filedand co-pending patent application entitled “Ferrule for optical waveguide,” filed on Oct. 23, 2006, and assigned application Ser. No.11/551,893.

FIELD OF THE INVENTION

The present invention relates generally to connecting optical waveguides of different components to one another, and more specifically toa ferrule for an optical wave guide to connect the optical wave guidesof different components together.

BACKGROUND OF THE INVENTION

Traditionally, data communications among different components ofcomputing devices and of computing systems have occurred via electricalwiring, such as copper wiring on printed circuit boards. However, withthe increasing speed of various computing components, such as processorsand memory, electrical wiring as a connection mechanism has become abottleneck to transferring data among different components. Therefore,manufacturers have been looking to alternatives other than electricalwiring to connect different components together for data communicationpurposes.

One alternative is to communicate data among different components ofcomputing devices and of computing systems using light. Such opticaldata transfer is typically significantly faster than electrical datatransfer using electrical wiring, and further does not have the limitsthat electrical data transfer does. Optical wave guides in particularhave become a seriously considered candidate for optically transferringdata among different components.

To optically connect different printed circuit boards together, however,a connector is typically required. While light has excellent propagationcharacteristics in general, a large amount of loss of the light mayoccur at the connection point if a precise connection between theoptical wave guides of two circuit boards is not achieved. A connectorfor optically connecting the optical wave guides of two such componentsto one another should also be able to be mechanically attached anddetached as needed. Mechanical attachment of a connector to the opticalwave guides of the components should thus provide for precise opticalconnection between the components.

For these and other reasons, therefore, there is a need for the presentinvention.

SUMMARY OF THE INVENTION

The invention relates generally to a ferrule for an optical wave guide.An apparatus of an embodiment of the invention includes an optical waveguide and a ferrule. The optical wave guide has a prespecifiedhorizontal-positioning surface and a prespecified vertical-positioningsurface. The ferrule is to precisely couple with the optical wave guide.The ferrule defines a first datum plane mating with the prespecifiedvertical-positioning surface of the optical wave guide to preciselymechanically vertically position the optical wave guide within theferrule. The ferrule defines a second datum plane mating with theprespecified horizontal-positioning surface of the optical wave guide toprecisely mechanically horizontally position the optical wave guidewithin the ferrule.

For instance, in one embodiment, the ferrule may include a bottomportion defining a center trench that has a lower horizontal surfacedefining the first datum plane. The optical wave guide may include abottom substrate having a lower horizontal surface defining theprespecified vertical-positioning surface of the optical wave guide andmating with the lower horizontal surface of the center trench of theferrule. The center trench of the ferrule may have a lug extending fromthe lower horizontal surface thereof that defines the second datumplane. The bottom substrate of the optical wave guide may further have anotch within its lower horizontal surface defining the prespecifiedhorizontal-positioning surface of the optical wave guide and thatcorresponds to and mates with the lug extending from the center trenchof the ferrule.

In another embodiment, the ferrule may include a bottom portion defininga center trench having a lower horizontal surface and one or morestepped upper horizontal surfaces to either side of the lower horizontalsurface. The stepped upper horizontal surfaces define the first datumplane. The optical wave guide may include a cladding layer having one ormore lower horizontal surfaces defining the prespecifiedvertical-positioning surface of the optical wave guide and mating withthe stepped upper horizontal surfaces of the center trench of theferrule. The center trench of the bottom portion of the ferrule mayfurther have one or more vertical side surfaces, at least one of whichdefine the second datum plane. The optical wave guide may further have acore pattern to transmit light, and a dummy core pattern that does nottransmit light but that has one or more vertical side surfaces. At leastone of the vertical side surfaces of the dummy core pattern define theprespecified horizontal positioning surface of the optical wave guideand mate with corresponding at least one of the vertical side surfacesof the center trench of the ferrule.

At least some embodiments of the invention provide for advantages overthe prior art. The ends of two optical wave guides, such as extendingfrom two different components of a computing device or of a computingsystem, may be precisely optically (and mechanically) mated with oneanother via the ferrule. The optical wave guides are both inserted intothe ferrule, where the various aspects of the optical wave guides and ofthe ferrule as has been described provides for precise mechanical andoptical mating between the optical wave guides and the ferrule and thusbetween the optical wave guides themselves. A cover, or top portion, ofthe ferrule snaps onto the bottom portion of the ferrule after insertionof the optical wave guides into the bottom portion, so that the opticalwave guides remain connected to one another. Detaching the top portionof the ferrule thus allows for disconnection of the optical wave guides.

Still other aspects, advantages, and embodiments of the invention willbecome apparent by reading the detailed description that follows, and byreferring to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings referenced herein form a part of the specification.Features shown in the drawing are meant as illustrative of only someembodiments of the invention, and not of all embodiments of theinvention, unless otherwise explicitly indicated, and implications tothe contrary are otherwise not to be made.

FIG. 1 is a diagram in which the optical wave guides of two componentsare precisely connected to one another, according to an embodiment ofthe invention.

FIG. 2 is a cross-sectional diagram of a ferrule and an optical waveguide, according to an embodiment of the invention.

FIG. 3 is a partial cross-sectional diagram of the ferrule and theoptical wave guide of FIG. 2, according to another embodiment of theinvention.

FIG. 4 is a flowchart of a method for fabricating the optical wave guideof FIG. 2, according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following detailed description of exemplary embodiments of theinvention, reference is made to the accompanying drawings that form apart hereof, and in which is shown by way of illustration specificexemplary embodiments in which the invention may be practiced. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the invention. Other embodiments may be utilized,and logical, mechanical, and other changes may be made without departingfrom the spirit or scope of the present invention. The followingdetailed description is, therefore, not to be taken in a limiting sense,and the scope of the present invention is defined only by the appendedclaims.

FIG. 1 shows a system 100, according to an embodiment of the invention.The system 100 includes two components 102 and 104. The components 102and 104 may be printed circuit boards, memory, processors, or othertypes of computing components. The components 102 and 104 may be part ofthe same computing system, and/or parts of the same computing device.The component 102 includes an optical wave guide 106 for optical datacommunication therewith, and the component 104 includes an optical waveguide 108 for optical data communication therewith.

The optical wave guides 106 and 108 have ferrules 110A and 110B,respectively, to precisely connect the optical wave guides 106 and 108precisely together, optically and/or mechanically. An apparatus of oneembodiment of the invention can be considered as including one of theferrules 110A and 110B and a corresponding one of the optical waveguides 106 and 108. The ferrule 110A is a male ferrule having pins 112Aand 112B, collectively referred to as the pins 112, whereas the ferrule110B is a female ferrule having holes 114A and 114B, collectivelyreferred to as the holes 114.

To precisely connect the optical wave guides 106 and 108 together, thepins 112 of the ferrule 110A are aligned with and securely inserted intothe holes 114 of the ferrule 110B, as indicated by the arrow 116. In oneembodiment, a cover may then be latched onto and over both the ferrules110A and 110B to secure them in place, which is not particularlydepicted in FIG. 1. In another embodiment, such a cover may not beemployed. Thus, the ferrules 110A and 110B precisely align the opticalwave guides 106 and 108 together to ensure that satisfactory opticalcoupling occurs between the optical wave guides 106 and 108.

Other embodiments of the invention can vary from the basic depiction ofFIG. 1. For instance, one or both of the ferrules 110A and 110B may bepermanently mounted to one or both of the components 102 and 104. Ingeneral, in at least some embodiments, it can be said that the ferrules110A and 110B are precisely mechanically connected to both the opticalwave guides 106 and 108, so that the optical wave guides 106 and 108 areprecisely optically coupled to one another.

FIG. 2 shows a cross section of an apparatus 200 including the ferrule110 and an optical wave guide 202, according to an embodiment of theinvention. The optical wave guide 202 may, for instance, be the opticalwave guide 106 or 108 of FIG. 1, whereas the ferrule 110 may, forinstance, be the ferrule 110A or 110B of FIG. 1. There are two datumplanes 204 and 206 defined by the ferrule 110 within FIG. 2. The datumplane 204 provides for precise mechanical positioning of the opticalwave guide 202 within the ferrule 110 horizontally, whereas the datumplane 206 provides for precise mechanical positioning of the opticalwave guide 202 within the ferrule 110 vertically, as will be describedin more detail.

The ferrule 110 includes a bottom portion 208 and a top portion 210. Thebottom portion 208 includes a center trench 212 that is substantiallylocated within the center of the ferrule 110, from left to right. Thelower horizontal surface of the center trench 212 defines the datumplane 206. A lug 220 extends from the lower horizontal surface of thecenter trench 212 of the ferrule 110. One of the side surfaces, such asthe left side surface in the example of FIG. 2, of the lug 220 definesthe datum plane 204.

The bottom portion 208 also is depicted in FIG. 2 as including two sidetrenches 216A and 216B, collectively referred to as the side trenches216, to either side of the center trench 212. The side trenches 216 areshallower than the center trench 212, such that the latter is verticallydeeper than the former. The side trenches 216 are receptive tocorresponding positioning pins 218A and 218B, collectively referred toas the pins 218. The pins 218 may be pins employed to properly positionthe bottom portion 208 while the center trench 212 and the lug 220 arebeing fabricated therein, such as in an injection-molding process thatemploys an injection-molding tool having such pins 218.

In one embodiment, the pins 218 may be the pins 112 of the ferrule 110Aof FIG. 1, and the trenches 216 may be the holes 114 of the ferrule 110Bof FIG. 1. Therefore, where the ferrule 110 is the ferrule 110A, itincludes the pins 218, whereas where the ferrule 110 is the ferrule110B, it does not include the pins 218. The ferrule 110 of FIG. 2 cantherefore be considered a composite ferrule, covering both the case ofthe ferrule 110A and the case of the ferrule 110B.

Injection molding is particular allows the ferrule 110 to have precisetolerances within a few micrometers. The distance from the centers ofthe pins 218 to the datum plane 204 is particularly important to beprecisely controlled, since the datum plane 204 provides for precisehorizontal positioning of the optical wave guide 202 within the ferrule110. Likewise, the distance from the centers of the pins 218 to thedatum plane 206 is particularly important to be precisely controlled,since the datum plane 206 provides for precise vertical positioning ofthe optical wave guide 202 within the ferrule 110.

The top portion 210 of the ferrule 110 has a bottom surface from which abottom element 214 extends vertically downward. The bottom element 214is sized width-wise to correspond to the width of the center trench 212of the bottom portion 208. Thus, the bottom element 214 of the topportion 210 fits securely within the center trench 212 of the bottomportion 208 of the ferrule 110.

The optical wave guide 202 includes a bottom substrate 222, a bottomcladding layer 224, an optical wave guide core pattern made up ofpattern portions 228A, 228B, . . . , 228N, collectively referred to asthe pattern portions 228, and an upper cladding layer 226. The substrate222 has a lower horizontal surface that defines a prespecifiedvertical-positioning surface of the optical wave guide 202 in theembodiment of FIG. 2. This prespecified vertical-positioning surfacemates with or to the datum plane 206 for precise mechanical positioningof the optical wave guide 202 within the ferrule 110, vertically. Thatis, the lower horizontal surface of the substrate 222 mates with thelower horizontal surface of the center trench 212 of the ferrule 110 forprecise mechanical vertical positioning of the optical wave guide 202within the ferrule 110. Where the former comes into contact with (i.e.,mates with) the latter, it can be said and known that the optical waveguide 202 is properly and precisely mechanically vertically positionedwithin the ferrule 110.

The lower horizontal surface of the substrate 222 of the optical waveguide 202 also has a notch 230 therein that defines a prespecifiedhorizontal-positioning surface of the optical wave guide 202 in theembodiment of FIG. 2. More particularly, one of the side surfaces, suchas the left side surface in the example of FIG. 2, of the notch 230defines the prespecified horizontal-positioning surface of the opticalwave guide 202 in the embodiment of FIG. 2. This prespecifiedhorizontal-positioning surface mates with or to the datum plane 204 forprecise mechanical positioning of the optical wave guide 202 within theferrule 110, horizontally. That is, the left side surface of the notch230 mates with the left side surface of the lug 220 extending from thelower horizontal surface of the center trench 212 of the ferrule 110 forprecise mechanical horizontal positioning of the optical wave guide 202within the ferrule 110. Where the former comes into contact with (i.e.,mates with) the latter, it can be said and known that the optical waveguide 202 is properly and precisely mechanically horizontally positionedwithin the ferrule 110.

The bottom cladding layer 224 is fabricated on the bottom substrate 222of the optical wave guide 202. The pattern portions 228 of the corepattern of the optical wave guide 202 are fabricated on the bottomsubstrate 222, but are of a different material than the bottom substrate222. The core pattern (i.e., the pattern portions 228) enable light tobe transmitted through the optical wave guide 202, such as light whichmay carry data transmitted to or from a component of a computing systemor of a computing device. The upper cladding layer 226 is thenfabricated on the core pattern (and on the bottom cladding layer 224),such as from the same material as of the bottom cladding layer 224.

In operation, the top portion 210 of the ferrule 110 is removed, and apair of optical wave guides, such as including the optical wave guide202, are inserted into the bottom portion 208 of the ferrule 110. Theoptical wave guides are mechanically precisely positioned within theferrule 110 both vertically and horizontally as has been described, toensure that the optical wave guides are effectively optically coupled toone another. Thereafter, the top portion 210 is snapped back into thebottom portion 208, where the top portion 210 makes forcible contactwith the upper cladding layer 226 of the optical wave guides to keep theoptical wave guides in place as have been precisely mechanically alignedvertically and horizontally within the ferrule 110. That is, the topportion 210 maintains pressure on the optical wave guides to keep themin place after they have been inserted into the bottom portion 208 in aprecisely aligned manner.

The lug 220 and the notch 230 have been depicted in FIG. 2 as being atleast substantially rectangular in shape. By comparison, FIG. 3 shows aportion of the apparatus 200 in which the lug 220 and the notch 230 areV-shaped, according to an embodiment of the invention. As before, thelug 220 extends from the lower horizontal surface of the center trench212 within the bottom portion 208 of the ferrule 110, where this lowerhorizontal surface defines the datum plane 206. In the example of FIG.3, the left side surface of the lug 220 defines the datum plane 204.

The notch 230 within the lower horizontal surface of the substrate 222corresponds to and mates with the lug 220. This lower horizontal surfacedefines the prespecified vertical-positioning surface of the opticalwave guide 202 that mates with or to the datum plane 206. In the exampleof FIG. 3, the left side surface of the notch 230 defines theprespecified horizontal-positioning surface of the optical wave guide202, which matches with or to the datum plane 204. The V-shaped notch230 and the V-shaped lug 220 of FIG. 3 can provide for more accurate andprecise positioning of the optical wave guide 202 within the ferrule 110as compared to the rectangularly shaped notch 230 and the rectangularlyshaped lug 220 of FIG. 2.

FIG. 4 shows a method 400 for fabricating the optical wave guide 202 ofFIG. 2, according to an embodiment of the invention. The center notch230 is fabricated within the lower horizontal surface of the substrate222 of the optical wave guide 202 (402). For instance, the substrate 222may be turned upside down, so that the lower horizontal surface thereoffaces upward, and the notch 230 diced within the substrate 222 using adicing tool. In one embodiment, the width and depth of the notch 230 maybe forty and seventy-five micrometers, respectively. In the particularembodiment of FIG. 2, at least one side of the notch 230 isperpendicular to the surface of the substrate 202, for pushing againstthe lug 220 for proper and precise positioning of the optical wave guide202 within the ferrule 110, as has been described. The substrate 222 maybe a polyethylene terephthalate (PET) film, or another type of film, andmay be 100 micrometers in height.

Next, the substrate 222 is turned over so that the center notch 230faces downwards, and the bottom cladding layer 224 is fabricated on thesubstrate 222 (404). The substrate 222 may be affixed to another entityduring the fabrication process of the entire optical wave guide 202,which is referred to herein as the base substrate, and which isdifferent than the substrate 222. Acrylic or another material may bespincoated as the bottom cladding layer 224 onto the substrate 222 usinga spincoating tool. In one embodiment, the thickness of the bottomcladding layer 224 is twenty micrometers. After spincoating, thesubstrate 222 with the bottom cladding layer 224 thereon is baked on ahot plate, such as at 100 degrees Celsius (° C.) for twenty minutes, anddried. Thereafter, the bottom cladding layer 224 may be exposed toultraviolet (UV) or other radiation using an appropriate tool, as can beappreciated by those of ordinary skill within the art, such as for fiveminutes, and then baked again, such as at 150 degrees ° C. for thirtyminutes.

The core pattern—that is, the pattern portions 228 thereof—is thenfabricated on the bottom cladding layer 224 (406). The material of thecore pattern, which is different than the material of the bottomcladding layer 224 in that it transmits light, whereas the material ofthe bottom cladding layer 224 does not, may be spincoated onto thebottom cladding layer 224 using a spincoating tool, so as to achieve athickness, for example, of fifty micrometers. The substrate 222 with thebottom cladding layer 224 and the resulting added core pattern materialmay then be baked on a hot plate at 100° C. for twenty minutes anddried. Thereafter, the optical wave guide 202 as assembled thus far canbe placed within an aligning tool to expose the core pattern material toUV or other radiation through a photomask containing the core patterncorresponding to the portions 228 to be fabricated.

The photomask is aligned specifically relative to the feature of thesubstrate 22 corresponding to the datum line 204, such as the left sidesurface of the notch 230, as has been described. This ensures that themask, and thus the core pattern made up of the pattern portions 228, isprecisely aligned or positioned relative to the notch 230, and thereforeultimately to the datum line 204. Exposure may be achieved for a periodof time such as ten minutes. Thereafter, the core pattern material isdeveloped to remove either those parts thereof that were exposed toradiation (i.e., positive photolithography), or those that were not(i.e., negative photolithography). The result is that only the portions228 of the core pattern material remain. The process describedheretofore in this paragraph is conventional photolithographicalfabrication. After developing, the pattern portions 228, as well as theexposed portions of the bottom cladding layer 224, may be exposed forfive minutes or another period of time to UV or other radiation using anappropriate tool, as can be appreciated by those of ordinary skillwithin the art, and then baked again, such as for 150° C. for sixtyminutes.

Finally, the upper cladding layer 226 of the optical wave guide 202 isfabricated on the core pattern (and on the exposed portions of thebottom cladding layer 224) (408). For instance, a spincoating tool maybe used to spincoat the same material as that of which the bottomcladding layer 224 is made, such that the upper cladding layer 226 has athickness of twenty micrometers, and is thus made from the same acrylicor other material as the bottom cladding layer 224. The resultingoptical wave guide 202 may then be baked on a hot plate at 100° C. fortwenty minutes, and exposed to UV or other radiation one last time,using an appropriate tool, for five minutes. Thereafter, the opticalwave guide 202 is baked one last time at 150° C. for thirty minutes. Theoptical wave guide 202 is removed from the base substrate, and can thenbe cut using the same dicing tool as was used to form the notch 230 atthe beginning of the method 400 of FIG. 4.

FIG. 5 shows a cross section of the apparatus 200 including the ferrule110 of FIG. 2 and the optical wave guide 202 of FIG. 2, according to analternate embodiment of the invention. There are again two datum planes204 and 206 defined by the ferrule 110 within FIG. 5. The datum plane204 provides for precise mechanical positioning of the optical waveguide 202 within the ferrule 110 horizontally, whereas the datum plane206 provides for precise mechanical positioning of the optical waveguide 202 within the ferrule 110 vertically. Operation of the apparatus200 of the embodiment of FIG. 5 is the same as that as in the embodimentof FIG. 2, except as explained differently below.

The ferrule 110, as before, includes the bottom portion 208 and the topportion 210. The bottom portion 208 includes the center trench 212 andthe side trenches 216 (receptive to the pins 218), as in FIG. 2.However, the center trench 212, besides including the lower horizontalsurface, also includes stepped upper horizontal surfaces 502A and 502B,collectively referred to as the stepped upper horizontal surfaces 502,in the embodiment of FIG. 5. The surfaces 502 are upper surfaces of thecenter trench 212 in that they are shallower, and not as deep, as thelower horizontal surface. The surfaces 502 are stepped in that thetrench steps downward from the surfaces 502 to the lower horizontalsurface.

The stepped upper horizontal surfaces 502 of the center trench 212 ofthe bottom portion 208 of the ferrule 110 define the datum plane 206.Furthermore, the center trench 212 of the bottom portion 208 includestwo vertical side surfaces. One of these vertical side surfaces definesthe datum plane 204. In the example of FIG. 5, the left vertical sidesurface defines the datum plane 204.

The top portion 210 of the ferrule 110 has a bottom surface from which abottom element 214 extends vertically downward, as in FIG. 2. The bottomelement 214 is sized width-wise to correspond to the width of the centertrench 212 of the bottom portion 208. Thus, the bottom element 214 ofthe top portion 210 fits securely within the center trench 212 of thebottom portion 208 of the ferrule 110.

The optical wave guide 202 includes the cladding layer 224, the opticalwave guide core pattern made up of the pattern portions 228, thecladding layer 226, and a so-called dummy optical wave guide corepattern made up of pattern portions 504A and 504B, collectively referredto as the dummy pattern portions 504. It is noted that in oneembodiment, fabrication of the optical wave guide 202 of FIG. 5 may beachieved similarly to that of FIG. 2 as described in the method 400 ofFIG. 4. The dummy core pattern may be fabricated at the same time as theactual core pattern, but is referred to as a dummy pattern in that it isnot actually used for light transmission purposes (although it may becapable of doing so). Also, during fabrication, the cladding layer 226may be fabricated first, then the pattern portions 228 and 504 arefabricated, and finally the cladding layer 224 is fabricated. Thus, theoptical wave guide 202 is flipped so that it is inserted cladding layer224 first into the ferrule 110, as depicted in FIG. 5.

The cladding layer 226 of the optical wave guide 202 is fabricated sothat it is sufficiently wide to contact the stepped upper horizontalsurfaces 502 of the center trench 212 of the bottom portion 208 of theferrule 110. Thus, the cladding layer 226 has two lower horizontalsurfaces—a left lower surface contacting the surface 502A and a rightlower surface contacting the surface 502B—that define a prespecifiedvertical-positioning surface of the optical wave guide 202 in theembodiment of FIG. 5. This prespecified vertical-positioning surfacemates with or to the datum plane 206 for precise mechanical positioningof the optical wave guide 202 within the ferrule 110, vertically. Thatis, the lower horizontal surfaces of the cladding layer 226 mate withthe stepped upper horizontal surfaces 502 of the center trench 212 ofthe ferrule 110 for precise mechanical vertical positioning of theoptical wave guide 202 within the ferrule 110. Where the former comesinto contact with (i.e., mates with) the latter, it can be said andknown that the optical wave guide 202 is properly and preciselymechanically vertically positioned within the ferrule 110.

The dummy pattern portions 504 of the dummy core pattern of the opticalwave guide 202 have two vertical side surfaces, a left vertical sidesurface at the left-most surface of the portion 504A, and a rightvertical side surface at the right-most surface of the portion 504B. Oneof these vertical side surfaces defines a prespecifiedhorizontal-positioning surface of the optical wave guide 202 in theembodiment of FIG. 5. In the example of FIG. 5, the left vertical sidesurface of the dummy pattern portions 504 defines the prespecifiedhorizontal-positioning surface of the optical wave guide. Thisprespecified horizontal-positioning surface mates with or to the datumplane 204 for precise mechanical positioning of the optical wave guide202 within the ferrule 110, horizontally. That is, the left side surfaceof the dummy pattern portion 504A mates with the left side surface ofcenter trench 212 of the ferrule 110 for precise mechanical horizontalpositioning of the optical wave guide 202 within the ferrule 110. Wherethe former comes into contact with (i.e., mates with) the latter, it canbe said and known that the optical wave guide 202 is properly andprecisely mechanically horizontally positioned within the ferrule 110.

It is noted that, although specific embodiments have been illustratedand described herein, it will be appreciated by those of ordinary skillin the art that any arrangement calculated to achieve the same purposemay be substituted for the specific embodiments shown. This applicationis thus intended to cover any adaptations or variations of embodimentsof the present invention. Therefore, it is manifestly intended that thisinvention be limited only by the claims and equivalents thereof

1. A method comprising: fabricating a center notch within a substrate ofan optical wave guide; fabricating a bottom cladding layer onto thesubstrate with the center notch positioned downward; fabricating on thebottom cladding layer a core pattern capable of transmitting lighttherethrough; and, fabricating an upper cladding layer onto the corepattern of the bottom cladding layer.
 2. The method of claim 1, whereinfabricating the center notch within the substrate of the optical waveguide comprises dicing the center notch within the substrate of theoptical wave guide using a dicing tool.
 3. The method of claim 1,wherein fabricating the bottom cladding layer onto the substratecomprises: spincoating an acrylic material onto the substrate and ofwhich the bottom cladding layer is made, using a spincoating tool; and,baking the substrate onto which the acrylic material has been spincoatedon a hot plate.
 4. The method of claim 3, wherein fabricating on thebottom cladding layer the core pattern capable of transmitting lighttherethrough comprises: spincoating a material onto the bottom claddinglayer and of which the core pattern is made, using a spincoating tool;baking the substrate onto which the acrylic material and the materialhave been spincoated is made on a hot plate; aligning the notch with amask for the core pattern to precisely position the mask for the corepattern relative to the notch; and, photolithographically fabricatingthe core pattern within the material spincoated on the bottom claddinglayer using the mask as has been precisely positioned.
 5. The method ofclaim 1, wherein fabricating the bottom cladding layer onto the corepattern comprises: spincoating an acrylic material onto the core patternand of which the bottom cladding layer is made, using a spincoatingtool; and, baking the substrate onto which the acrylic material has beenspincoated on a hot plate.